212251809 has 16 divisors (see below), whose sum is σ = 352834560. Its totient is φ = 110260560.

The previous prime is 212251801. The next prime is 212251829. The reversal of 212251809 is 908152212.

It is not a de Polignac number, because 212251809 - 2³ = 212251801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (212251801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 459189 + ... + 459650.

It is an arithmetic number, because the mean of its divisors is an integer number (22052160).

Almost surely, 2^212251809 is an apocalyptic number.

It is an amenable number.

212251809 is a deficient number, since it is larger than the sum of its proper divisors (140582751).

212251809 is a wasteful number, since it uses less digits than its factorization.

212251809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918860.

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 212251809 is about 14568.8643689205. The cubic root of 212251809 is about 596.5091824870.

The spelling of 212251809 in words is "two hundred twelve million, two hundred fifty-one thousand, eight hundred nine".